The suppression of behavior that occurs in instrumental extinction is strikingly specific to the response. In contrast, Steinfeld and Bouton (2022) recently reported that inhibition developing in an operant feature-negative (FN) discrimination is not specific to the response. In two experiments, we tested two potential explanations of why inhibition in FN learning is relatively response-general. In each, we used Steinfeld and Bouton's method and concurrently trained two FN discriminations with different operant responses (AR1+/ABR1- and CR2+/CDR2-). We then assessed the extent to which the inhibitory cues (B and D) suppressed the response they were trained with (same-response inhibition) and the alternative response (cross-response inhibition). Experiment 1 tested the idea that FN inhibition might be response-general because it can create strong inhibition. Rats received either 3, 6, or 12 sessions of FN discrimination training (Steinfeld and Bouton's rats had received 12). Inhibition was response-general at every level of training. In Experiment 2, the inhibitors (B and D) were first trained as cues that set the occasion for R1 and R2 (respectively) before they were turned into inhibitors in the FN discriminations. In the end, there was less cross-response inhibition, and thus more response-specificity. We suggest that inhibition in FN learning may be response-general because the unambiguous inhibitory cue (B or D) can draw attention away from the response.

To determine whether the punishment of a discriminated operant behavior has effects that are specific to the punished response, rats were reinforced for performing two different instrumental responses (lever pressing and chain pulling) in the presence of a single discriminative stimulus (S). They were then either punished with mild footshock for performing one of the responses (R1) in S, or they received the same shocks in a noncontingent manner while performing R1 in S (i.e., a yoked control). In final tests of both R1 and R2 in S, the punished rats were more suppressed to R1 than R2, but the yoked rats were not. The results extend previous results with extinction rather than punishment learning (Bouton, Trask, & Carranza-Jasso, 2016) and support a larger parallel between extinction and punishment of both free-operant and discriminated-operant responding. Punishment is like extinction in creating a response-specific inhibition of either free or discriminated operant behavior.

In recent years, a growing number of pre-clinical studies have made use of the social abilities of mice, asking how gene variants (e.g., null, transgenic or mutant alleles) give rise to abnormalities in neurodevelopment. Two distinct courses of research provide the foundation for these studies. One course has mostly focused on how we can assess "sociability" using metrics, often automated, to quantitate mouse approach and withdrawal responses to a variety of social stimuli. The other course has focused on psychobiological constructs that underlie the socio-emotional capacities of mice, including motivation, reward and empathy. Critically, we know little about how measures of mouse sociability align with their underlying socio-emotional capacities. In the present work, we compared the expression of sociability in adolescent mice from several strains versus a precisely defined behavioral model of empathy that makes use of a vicarious fear learning paradigm. Despite substantial strain-dependent variation within each behavioral domain, we found little evidence of a relationship between these social phenotypes (i.e., the rank order of strain differences was unique for each test). By contrast, emission of ultrasonic vocalizations was highly associated with sociability, suggesting that these two measures reflect the same underlying construct. Taken together, our results indicate that sociability and vicarious fear learning are not manifestations of a single, overarching social trait. These findings thus underscore the necessity for a robust and diverse set of measures when using laboratory mice to model the social dimensions of neuropsychiatric disorders.

Executive functioning and happiness are each associated with successful learning and other desirable individual and societal outcomes; however, it is unclear whether a relation exists between them. Executive regulation of happiness pursuits in daily life, operationalized as hedonic (e.g., pursuing pleasure) and eudaimonic (e.g., pursuing personal growth) motives for action, may be a way the constructs relate to each other. In this initial investigation, we aimed to explore whether objectively measured executive functioning skills relate to happiness motives. A sample of 119 college students completed six objective neuropsychological measures of executive functioning and self-reported levels of hedonic and eudaimonic motives for action in daily life. Correlation and regression analyses examined the relations among temporal discounting and two latent executive functioning factors (inhibitory control and working memory) with hedonic and eudaimonic motives, as well as their interaction. Results suggested a possible association between higher levels of eudaimonic motives and preference for higher delayed rewards, as well as poorer working memory. Further analyses suggested that endorsing high levels of eudaimonic and hedonic motives simultaneously (i.e., the "full life") was associated with poorer inhibitory control and working memory performance, whereas endorsing low levels of both simultaneously (i.e., the "empty life") was associated with a preference for more immediate monetary rewards. Findings are discussed in the context of goal conflict and risk assessment among individuals who endorse the "full life". Overall, these findings suggest that complex relations may exist between executive functioning and trait-level happiness pursuits, and have implications for possible interventions aimed at enhancing happiness-related motives and cognitive processes to facilitate learning. Given the exploratory nature of the present study, further investigations are necessary.

Delay discounting (DD) describes choices between small, immediate rewards and larger, delayed rewards. Individuals who are high in DD favor small, immediate rewards, and this preference is related to health behaviors including higher energy intake, smoking and less physical activity. Episodic future thinking (EFT) is an intervention in which one thinks about personal positive future events and this decreases DD in adults and children. In previous studies episodic events have been presented as written or auditory cues. Episodic future images are also imagined visually, but the impact of personal visual cues has not been tested. Research examining sensory modality and semantic memory has shown drawn items are associated with better recall than writing or viewing provided images. This study compared drawn versus written episodic future or recent cues on DD. Sixty-nine adults were randomized to one of three groups; EFT-written, EFT-drawn or Episodic recent thinking (ERT)-written cues, and completed a computerized adjusting amount DD task cued with episodic events. Results showed both written and drawn EFT cues had a larger effect on DD than ERT-written cues and individual differences in immediate time perspective moderated this effect. This suggests that drawn and written cues can have similar effects on DD, providing future clinical work flexibility in how to present cues in the field. In addition, presenting drawn cues may improve DD for individuals who have an immediate time perspective.

Amazon Mechanical Turk (MTurk) is a crowdsourcing marketplace providing researchers with the opportunity to collect behavioral data from remote participants at a low cost. Recent research demonstrated reliable extinction effects, as well as renewal and resurgence of button pressing with MTurk participants. To further examine the generality of these findings, we replicated and extended these methods across six experiments arranging reinforcement and extinction of a target button press. In contrast to previous findings, we did not observe as reliable of decreases in button pressing during extinction (1) after training with VR or VI schedules of reinforcement, (2) in the presence or absence of context changes, or (3) with an added response cost for button pressing. However, we found that that a 1-point response cost for all button presses facilitated extinction to a greater extent than the absence of response cost. Nevertheless, we observed ABA renewal of button pressing when changing background contexts across phases and resurgence when extinguishing presses on an alternative button. Our findings suggest that MTurk could be a viable platform from which to ask and address questions about extinction and relapse processes, but further procedural refinements will be necessary to improve the replicability of control by experimental contingencies.

Low motivation to learn in undergraduate general education courses hinders learning. Research has identified strategies that increase motivation to learn before students are asked to learn content (e.g., outlining the utility of the course material for future careers). Extending this work, we propose that learning any material in a course may beget motivation to learn more, in line with the notion that the process of learning itself may spark curiosity and interest. Across three populations (college-aged individuals on mTurk, large public university students, and small private university students), we found that watching a TED Talk video (i.e., exposure to new information, learning) pertaining to any topic led to an increase in motivation to continue learning about that topic and other topics more generally. These results reveal a need to broaden models of motivation to consider the importance of exposure to content to increase motivation to learn.

During the 2020 Covid-19 pandemic panic buying of food was reported by the media. Panic buying has received little attention within behavioural science. In this paper we suggest that optimality models of foraging under risk and uncertainty would be a fruitful place to begin developing useful and testable hypotheses about this behaviour. In making this case we relate panic buying to a general increase in foraging effort, which we characterize as an increase in purchasing and spending. We note two risks during the pandemic - that of food security and that of predation, where predation is understood as a perceived threat to life due to infection risk. Food security was effectively solved early on in the pandemic, whilst perceived threat to life has remained but diminished to some limited extent. We relate panic buying to food caching as a method of buffering risk and make six predictions about how this behaviour should present under food insecurity and perceived threat to life.

Pavlovian conditioning results in individual variation in the vigor and form of acquired behaviors. Here, we describe a general-process model of associative learning (HeiDI; How excitation and inhibition determine ideo-motion) that provides an analysis for such variation together with a range of other important group-level phenomena. The model takes as its starting point the idea that pairings of a conditioned stimulus (CS) and an unconditioned stimulus (US) result in the formation of reciprocal associations between their central representations. The asymptotic values of these associations and the rate at which these are reached are held to be influenced by the perceived salience of the CS (α) and US (β). Importantly, whether this associative knowledge is exhibited in behavior that reflects the properties of the CS (e.g., sign-tracking) or US (e.g., goal-tracking) is also influenced by the relative values of α and β. In this way, HeiDI provides an analysis for both quantitative and qualitative individual differences generated by Pavlovian conditioning procedures.

Renewal is the recovery of extinguished responding to a conditioned stimulus when testing occurs outside the extinction context. Renewal has been explained as the extinction context becoming a negative occasion setter during extinction. However, other mechanisms may contribute. Two recent studies showed (a) after extinction of a discrete cue, the extinction context can serve as a conditioned inhibitor, and (b) in some circumstances operational extinction of a conditioned inhibitor can reduce inhibition with respect to a transfer excitor while retaining inhibition with respect to the excitor used in inhibitory training. Here we examine the potential contribution of these phenomena to renewal. In the present experiment, all rats received fear-conditioning with a target cue in one context and extinction of that cue in a second context. Then half of the subjects received massive extinction of the extinction context (i.e., 24 h) while the other half received only handling. Finally, some subjects in each condition were tested for responding to the target cue in the extinction context, others in a second familiar context, and yet others in a third transfer context in which another fear cue had been extinguished. The results showed ABC renewal independent of whether subjects had or had not received context extinction. However, transfer of the inhibitory potential of the extinction context was observed only in subjects that did not receive context extinction. These results suggest an extinction context can serve as a stimulus-specific conditioned inhibitor, thereby contributing to renewal by decreasing responding to the target cue in an ABB control condition.

The higher response rates observed on ratio than on matched interval reward schedules has been attributed to the differential reinforcement of longer inter-response times (IRTs) on the interval contingency. Some data, however, seem to contradict this hypothesis, showing that the difference is still observed when the role of IRT reinforcement is neutralized by using a regulated-probability interval schedule (RPI). Given the mixed evidence for these predictions, we re-examined this hypothesis by training three groups of rats to lever press under ratio, interval and RPI schedules across two phases while matching reward rates within triads. At the end of the first phase, the master ratio and RPI groups responded at similar rates. In the second phase, an interval group yoked to the same master ratio group of the first phase responded at a lower rate than the RPI group. Post-hoc analysis showed comparable reward rates for master and yoked schedules. The experienced response-outcome rate correlations were likewise similar and approached zero as training progressed. We discuss these results in terms of a contemporary dual-system model of instrumental conditioning.

Clinicians often conduct indirect assessments (IAs; e.g., Durand & Crimmins, 1988; Iwata, DeLeon, & Roscoe, 2013; Matson & Vollmer, 1995) such as questionnaires and interviews with caregivers to gain information about the variables influencing problem behavior. However, researchers have found poor reliability and validity of IAs with respect to determining functional variables. There are numerous variables that might influence the efficacy of IAs as an assessment tool, one of which is the skill set of the person completing the IA. For example, it may be possible to increase the validity and reliability of IAs by having individuals with certain skill sets such as a background in behavior analysis and FBA ("experts") complete them. Thus, the purpose of this study was to compare the reliability (i.e., agreement with respect to function and specific IA questions) and validity (i.e., agreement between the outcome of IAs and a functional analysis) of IAs completed by caregivers and "experts" for each of eight children who emitted problem behavior. We found that experts were more likely than caregivers to agree on IA outcomes with respect to (a) overall interrater agreement, (b) item-by-item agreement, and (c) the highest-rated function(s) of problem behavior. Experts were also more likely to correctly identify the function(s), based on comparisons of the results of the IAs and FAs. In addition, caregivers were more likely to (a) disagree on hypothesized functions and (b) identify multiple incorrect functions. The use of experts for completing IAs could have significant impact on their utility and provide a novel method for more rapidly completing the FBA process and developing a function-based treatment.

Social interactions form the basis of a broad range of functions related to survival and mating. The complexity of social behaviors and the flexibility required for normal social interactions make social behavior particularly susceptible to disruption. The consequences of developmental insults in the social domain and the associated neurobiological factors are commonly studied in rodents. Though methods for investigating social interactions in the laboratory are diverse, animals are typically placed together in an apparatus for a brief period (under 30 min) and allowed to interact freely while behavior is recorded for subsequent analysis. A standard approach to the analysis of social behavior involves quantification of the frequency and duration of individual social behaviors. This approach provides information about the allocation of time to particular behaviors within a session, which is typically sufficient for detection of robust alterations in behavior. Virtually all social species, however, display complex sequences of social behavior that are not captured in the quantification of individual behaviors. Sequences of behavior may provide more sensitive indicators of disruptions in social behavior. Sophisticated analysis systems for quantification of behavior sequences have been available for many years; however, the required training and time to complete these analyses represent significant barriers to high-throughput assessments. We present a simple approach to the quantification of behavioral sequences that requires minimal additional analytical steps after individual behaviors are coded. We implement this approach to identify altered social behavior in rats exposed to alcohol during prenatal development, and show that the frequency of several pairwise sequences of behavior discriminate controls from ethanol-exposed rats when the frequency of individual behaviors involved in those sequences does not. Thus, the approach described here may be useful in detecting subtle deficits in the social domain and identifying neural circuits involved in the organization of social behavior.

In the current study, groups of mice were trained with either short (20 s) or long (120 s) conditioned stimulus (CS) durations associated with different rates of sucrose unconditioned stimulus (US) delivery, to examine whether different behavioral forms of cue-potentiated feeding in sated mice would be evoked. In training mice received presentations of an auditory CS for 20 s during which a sucrose US was delivered at a density of 1/9 s (Group-20-s). A second group of mice received an auditory CS for 120 s and a US density of 1/49 s (Group-120-s). During training, a shorter CS duration and higher rate of US delivery resulted in greater acquisition of food cup responding, and during the test stage Group-20-s mice also displayed higher CS evoked lick rates, though all mice showed cue-potentiated feeding. An analysis of licking microstructure also revealed that Group-120-s mice displayed CS evoked licking behavior that reflected an increase in the perceived palatability of the sucrose US. These findings are discussed with respect to the influence of CS interval and US density on associatively activated sensory and affective representations of a US, and contrast mediated effects resulting from presentation of excitatory and inhibitory conditioned stimuli.

Animals occupy territories in which resources such as food and shelter are often distributed unevenly. While studies of exploratory behavior have typically involved the laboratory rodent as an experimental subject, questions regarding what constitutes exploration have dominated. A recent line of research has utilized a descriptive approach to the study of rodent exploration, which has revealed that this behavior is organized into movement subsystems that can be readily quantified. The movements include home base behavior, which serves as a central point of attraction from which rats and mice organize exploratory trips into the remaining environment. In this review, we describe some of the features of this organized behavior pattern as well as its modulation by sensory cues and previous experience. We conclude the review by summarizing research investigating the neurobiological bases of exploration, which we hope will stimulate renewed interest and research on the neural systems mediating rodent exploratory behavior.

In an appetitively motivated procedure, we have previously reported that systemic treatment with the dopamine (DA) D1 receptor agonist SKF81297 (0.4 and 0.8 mg/kg) depressed acquisition at a 2 s inter-stimulus-interval (ISI), suitable to detect trace conditioning impairment. However since DA is involved in reinforcement processes, the generality of effects across appetitively- and aversively-motivated trace conditioning procedures cannot be assumed. The present study tested the effects of SKF81297 (0.4 and 0.8 mg/kg) in an established conditioned emotional response (CER) procedure. Trace-dependent conditioning was clearly shown in two experiments: while conditioning was relatively strong at a 3-s ISI, it was attenuated at a 30-s ISI. This was shown after two (Experiment 1) or four (Experiment 2) conditioning trials conducted in - as far as possible - the same CER procedure. Contrary to prediction, in neither experiment was there any indication that trace conditioning was attenuated by treatment with 0.4 or 0.8 mg/kg SKF81297. In the same rats, locomotor activity was significantly enhanced at the 0.8 mg/kg dose of SKF81297. These results suggest that procedural details of the trace conditioning variant in use are an important determinant of the profile of dopaminergic modulation.

The effect of US signalling and the US-CS interval in backward conditioning was assessed in mice. For one group of mice the presentation of food was signalled by a tone and for another group, food was unsignalled. For half of the mice, within each group, the presentation of food preceded a visual cue by 10 s. For the other half, food was presented at the start of the visual cue (0-s US-CS interval), resulting in simultaneous pairings of these events. A summation test and a subsequent retardation test were used to assess the inhibitory effects of backward conditioning in comparison to training with a non-reinforced visual cue that controlled for the possible effects of latent inhibition and conditioned inhibition caused as a consequence of differential conditioning. In the summation test unsignalled presentations of the US resulted in inhibition when the US-CS interval was 10 s, but not 0 s. Signalled presentations of the US resulted in inhibition, independent of the US-CS interval. In the retardation test, independent of US signalling, a US-CS interval of 10 s failed to result in inhibition, but an interval of 0 s resulted in greater conditioned responding to the backward CS than the control CS. A generalisation decrement account of the effect of signalling the US with a 0-s US-CS interval, which resulted in reduced responding in the summation test and faster acquisition in the retardation test, is discussed.

While the Odor Span Task (OST) was developed to assess working memory in rodents, it appears that odor ("What") and time since an odor was last reinforced ("When") jointly control responding in the OST. The OST uses an incrementing non-match to sample procedure such that the number of stimuli to remember increases during the session; the rodent is trained to remember stimuli within a session but not between sessions. We used a variation of the OST to add a "Where" dimension to the task to examine whether rodents could learn to respond to scents based on contextual cues as well. In Experiment 1, 6 rats well-trained on the OST procedure were exposed to four target scents in a holding cage before the OST session began [What-Where-When (WWW) condition]. When these target scents appeared in the OST, rats treated them as novel scents despite their being previously encountered that day; WWW responding was comparable to baseline (BL) responding. Controls were implemented to account for relative familiarity: frequency of target presentation and time since the target odor was presented. On both types of control probes, rats typically responded to target scents less than during WWW or BL conditions, took longer to make a response, and visited more comparison stimuli. In Experiment 2, the study was replicated adding reinforcement delivery for responding to pre-session presentation of target stimuli. Subjects were the same 6 rats plus 2 additional rats also well-trained on the OST. Results were similar to those from Experiment 1. These data indicate that the variables controlling performance on the OST task include stimulus is presented, (i.e., in which location) it was presented, and it was presented. Thus, the OST-probe methodology may provide a useful vehicle for the study of episodic-like memory processes in non-humans.

Recovery-from-extinction effects (e.g., spontaneous recovery, renewal, reinstatement, and facilitated reacquisition) have become the focus of much research in recent years. However, despite a great deal of empirical data, there are few theoretical explanations for these effects. This paucity poses a severe limitation on our understanding of these behavioral effects, impedes advances in uncovering neural mechanisms of response recovery, and reduces our potential to prevent relapse after exposure therapy. Towards correcting this oversight, this review takes prominent models of associative learning that have been used in the past and continue to be used today to explain Pavlovian conditioning and extinction, and assesses how each model can be applied to account for recovery-from-extinction effects. The models include the Rescorla-Wagner (1972) model, Mackintosh's (1975) attentional model, Pearce and Hall's (1980) attentional model, Wagner's (1981) SOP model, Pearce's (1987) configural model, McLaren and Mackintosh's (2002) elemental model, and Stout and Miller's (2007) SOCR (comparator hypothesis) model. Each model is assessed for how well it explains or does not explain the various recovery-from-extinction phenomena. We offer some suggestions for how the models might be modified to account for these effects in those instances in which they initially fail.

Faces are an important visual category for many taxa, and the human face is no exception to this. Because faces differ in subtle ways and possess many idiosyncratic features, they provide a rich source of perceptual cues. A fair amount of those cues are learned through social interactions and are used for future identification of individual humans. These effects of individual experience can be studied particularly well in hetero-specific face perception. Domestic dogs represent a perfect model in this respect, due to their proved ability to extract important information from the human face in socio-communicative interactions. There is also suggestive evidence that dogs can identify their owner or other familiar human individuals by using visual information from the face. However, most studies have used only dogs' looking behavior to examine their visual processing of human faces and it has been demonstrated only that dogs can differentiate between familiar and unknown human faces. Here, we examined the dog's ability to discriminate the faces of two familiar persons by active choice (approach and touch). Furthermore, in successive stages of the experiment we investigated how well dogs discriminate humans in different representations by systematically reducing the informational richness and the quality of the stimuli. We found a huge inter-individual and inter-stage variance in performance, indicating differences across dogs in their learning ability as well as their selection of discriminative cues. On a group level, the performance of dogs significantly decreased when they were presented with pictures of human heads after having learned to discriminate the real heads, and when - after relearning - confronted with the same pictures showing only the inner parts of the heads. However, as two dogs quickly mastered all stages, we conclude that dogs are able to discriminate people on the basis of information from their and by making active choices.

The olfactory span task (OST) uses an incrementing non-matching to sample procedure such that the number of stimuli to remember increases during the session. The number of consecutive correct responses (span length) and percent correct as a function of the memory load have been viewed as defining rodent working memory capacity limitations in several studies using the OST. However, the procedural parameters of the OST vary across experiments and their effects are not well understood. For example, in several studies, the number of stimuli to remember is confounded with the number of comparison stimuli displayed in the test arena. Experiment 1 addressed whether performance is influenced by the number of comparison choices available on any given trial (2, 5, 10) as well as the number of odor stimuli to remember during a session (12, 24, 36). Performance was most accurate when the number of stimuli to remember was low, as would be expected from a working memory interpretation of OST. However, accuracy was also affected by the number of comparison stimulus choices. High levels of accuracy were seen even with 36 odors, suggesting that the capacity for odor memory in rats was greater than suggested by previous research. Experiment 2 attempted to define this capacity by programming sessions with 36, 48 or 72 stimuli to remember in a group of rats that had previously received extensive OST training. Highly accurate performance (80% correct or better) was sustained throughout the session at even the greatest memory loads, arguing strongly against the notion that the OST models the limited capacity of human working memory. Experiment 3 explored the possibility that stimulus control in the OST is based on relative stimulus familiarity, rather than recognition of stimuli not yet presented during the current session. Number of odor cups visited increased with the number of comparisons in the arena, but rats rarely sampled all of the comparison odors before responding. However, on probe trials which included only stimuli that had been presented during the session, latency to respond and number of comparisons sampled was sharply increased. These data suggest that responding in the OST is determined not just by relative familiarity, but rather by a more specific "what-when" or perhaps "how long ago" form of stimulus control.

In resurgence, an operant behavior that has undergone extinction can return ("resurge") when a second operant that has replaced it itself undergoes extinction. The phenomenon may provide insight into relapse that may occur after incentive or contingency management therapies in humans. Three experiments with rats examined the impact of several variables on the strength of the resurgence effect. In each, pressing one lever (L1) was first reinforced and then extinguished while pressing a second, alternative, lever (L2) was now reinforced. When L2 responding was then itself extinguished, L1 responses resurged. Experiment 1 found that resurgence was especially strong after an extensive amount of L1 training (12 as opposed to 4 training sessions) and after L1 was reinforced on a random ratio schedule as opposed to a variable interval schedule that was matched on reinforcement rate. Experiment 2 found that after 12 initial sessions of L1 training, 4, 12, or 36 sessions of Phase 2 each allowed substantial (and apparently equivalent) resurgence. Experiment 3 found no effect of changing the identity of the reinforcer (from grain pellet to sucrose pellet or sucrose to grain) on the amount of resurgence. The results suggest that resurgence can be robust; in the natural world, an operant behavior with an extensive reinforcement history may still resurge after extensive incentive-based therapy. The results are discussed in terms of current explanations of the resurgence effect.

Prospective memory involves the encoding, retention, and implementation of an intended future action. Although humans show many forms of prospective memory, less is known about the future oriented processes of nonhuman animals, or their ability to use prospective memory. In this experiment, a chimpanzee named Panzee, who had learned to associate geometric forms called lexigrams with real-world referents, was given a prospective memory test. Panzee selected between two foods the one she wanted to receive more immediately. That food was scattered in an outdoor yard where she could forage for it. Also outdoors were lexigram tokens, one of which represented the food item that remained indoors throughout a 30 minute period, and that could be obtained if Panzee brought in the token that matched that food item. After foraging for the selected food item, Panzee consistently remembered to retrieve and return the correct token when food was available indoors, whereas on control trials involving no indoor food she rarely returned a token. This indicated that Panzee encoded information relevant to the future action of token retrieval after extended delays for one type of food, even when a more immediately preferred food was available.

Efforts to develop animal models of memory are critical for understanding the neural substrate of memory. Memory is essential for daily life and enables information to be stored and retrieved after seconds to years. The ability to remember episodes from the past is thought to be related to the ability to plan for the future. Here we focus on a particular aspect of prospective cognition, namely the ability to remember to take action when a future scenario occurs. This review focuses on a recently developed method to evaluate prospective memory in the rat. Available evidence suggests that rats remember to take action in the future, but little is known about the temporal specificity of such memories or about the flexibility and limitations of prospective memories. Recent studies that suggest that rats remember a specific past episode are reviewed to underscore potential approaches that may be used to explore the range and limits of prospective cognition. The review highlights some directions to explore, including the temporal specificity of prospective cognition, the range of flexibility or creativity within prospective cognition, and the constraints imposed by multiple motivational systems.

Recent studies have demonstrated that the expectation of reward delivery has an inverse relationship with operant behavioral variation (e.g., Stahlman, Roberts, & Blaisdell, 2010). Research thus far has largely focused on one aspect of reinforcement - the likelihood of food delivery. In two experiments with pigeons, we examined the effect of two other aspects of reinforcement: the magnitude of the reward and the temporal delay between the operant response and outcome delivery. In the first experiment, we found that a large reward magnitude resulted in reduced spatiotemporal variation in pigeons' pecking behavior. In the second experiment, we found that a 4-s delay between response-dependent trial termination and reward delivery increased variation in behavior. These results indicate that multiple dimensions of the reinforcer modulate operant response variation.

Pigeons show a preference for an alternative that provides them with discriminative stimuli (sometimes a stimulus that predicts reinforcement and at other times a stimulus that predicts the absence of reinforcement) over an alternative that provides them with non discriminative stimuli, even if the non discriminative stimulus alternative is associated with 2.5 times as much reinforcement (Stagner & Zentall, 1910). In Experiment 1 we found that the delay to reinforcement associated with the non discriminative stimuli could be reduced by almost one half before the pigeons were indifferent between the two alternatives. In Experiment 2 we tested the hypothesis that the preference for the discriminative stimulus alternative resulted from the fact that, like humans, the pigeons were attracted by the stimulus that consistently predicted reinforcement (the Allais paradox). When the probability of reinforcement associated with the discriminative stimulus that predicted reinforcement was reduced from 100% to 80% the pigeons still showed a strong preference for the discriminative stimulus alternative. Thus, under these conditions, the Allais paradox cannot account for the sub-optimal choice behavior shown by pigeons. Instead we propose that sub-optimal choice results from positive contrast between the low expectation of reinforcement associated with the discriminative stimulus alternative and the much higher obtained reinforcement when the stimulus associated with reinforcement appears. We propose that similar processes can account for sub-optimal gambling behavior by humans.

Pigeons prefer a positive discriminative (S+) stimulus that follows a less preferred event (a large number of required responses, a longer delay, or the absence of food) over a different S+ with a similar history of reinforcement that follows a more preferred event (a single required response, no delay, or food). We proposed that this phenomenon results from contrast (referred to as within-trial contrast) between the less preferred initial event and the signal for reinforcement. Delay reduction theory (Fantino, 1969) can account for these results by proposing that the less preferred initial event lengthens the duration of the trial, thereby allowing the S+ stimulus to occur later in the trial and thus become a better predictor of reinforcement. In the present experiments, we further explored this effect. In Experiment 1, we controlled for trial duration by using a fixed ratio response (30 pecks) as one initial event and the absence of pecking for the same duration as the other initial event (0 pecks). The pigeons showed a reliable preference for the positive stimulus that followed the least preferred initial event. In Experiment 2, we controlled for trial duration by using 30 pecks as one initial event and 1 peck followed by a delay that matched the duration of the preceding 30-peck trial. (Group Time Same). For Group Time Different, there was no delay following the 1-peck initial event. For Group Time Same, preference for the initial event negatively predicted the pigeons' preference for the S+ stimulus that followed, supporting the contrast account. A somewhat greater preference for the discriminative stimulus that followed the least preferred initial event was found for Group Time Different suggesting that in addition to contrast, delay reduction also may play a small role. However, the greater initial-event preference found for Group Time Different suggests that contrast can account for the group difference as well.

Reinforcing value and habituation are two processes that have been used to study eating behaviors, but no research has examined their relationship, how they relate to energy intake, and whether they respond in a similar manner to food deprivation. Twenty-two female subjects were randomized to food deprived or non-deprived conditions, and assessed for food reinforcement, habituation to food and ad libitum eating. Results showed food reinforcement and habituation are correlated (r = 0.62, p = 0.002) and both independently predict energy intake. Hierarchical regression showed that the rate of habituation accounted for 30 percent of the variance in eating (p = 0.008), and adding food reinforcement increased the amount of variance accounted for up to 57.5 percent (p < 0.05). This suggests that both processes may influence energy intake in a meal.

Three experiments with rat subjects examined resurgence of an extinguished instrumental response using the procedure introduced by Epstein (1983) with pigeons. There were three phases: (1) initial acquisition of pressing on a lever (L1) for pellet reward, (2) extinction of L1, and (3) a test session in which a second lever (L2) was inserted, briefly reinforced, and then extinguished. Experiment 1 confirmed that if pressing L2 delivered 20 pellets followed by extinction, rats would resume L1 responding in the final test. Experiment 2 compared the effects of response-contingent and non-contingent rewards delivered upon insertion of L2. Although insertion of L2 alone did not increase L1 responding, response-contingent and non-contingent rewards led to comparable increases in L1 responding. Experiment 3 found that the delivery of non-contingent pellets during extinction of L1, which would be expected to reduce the ability of pellets to set the occasion for the L1 response, also reduced the effects of both response-contingent and non-contingent rewards during the final test. The results indicate that in this method, the resurgence treatment leads to an increase in L1 pressing due to simple presentation of the pellet; delivering the reinforcer after extinction of L1 reinstates L1 responding by setting the occasion for the L1 response.

When animals code stimuli for later retrieval they can either code them in terms of the stimulus presented (as a retrospective memory) or in terms of the response or outcome anticipated (as a prospective memory). Although retrospective memory is typically assumed (as in the form of a memory trace), evidence of prospective coding has been found when response intentions and outcomes are particularly salient. At a more abstract level is the question of whether animals are able figuratively to travel back in time to recover memories of past events (episodic memory) and forward in time to predict future events (future planning). Although what would constitute adequate evidence of episodic memory and future planning is controversial, preliminary evidence suggests that animals may be capable of both forms of subjective time travel.